1. Field of the Invention
The present invention relates to a nucleic acid sequence segment, especially to a nucleic acid sequence segment that enhances expression of the recombinant protein segments. The present invention also relates to an expression vector, especially to an expression vector that enhances the expression of recombinant protein. The present invention also relates to a kit, especially to the kit comprising the expression vector and an antibody that can detect the expression of the expression vector.
2. Description of the Prior Arts
Since the physical and chemical properties, folding, structure stability, activity, and protein function can be affected by post-translational modification (PTM), PTM is an extremely important mechanism in biological cells. Phosphorylation is one of the most important post-translational modifications of proteins, and it is involved in a variety of different biological signal pathways; phosphorylation not only refers to a PO4 group binding to a protein or other molecules, but also be defined as an organic phosphate group leading into a molecule, therefore, phosphorylation plays a significant rule in biochemistry field because of its complicated regulation mechanism. Protein phosphorylation occurs at a specific amino acid (the major unit of protein) on which the serine is followed by a threonine Phosphorylation occurring on tyrosine is relatively less, and the location on tyrosine is wider because tyrosine can be purified by antibody easily. Phosphorylation and dephosphorylation respectively require specific enzymes to react, such as protein kinase and phosphatase that can react on particular location on amino acid sequence of the protein. Studies estimate that nearly a third of intracellular proteins are phosphorylated, and nearly half of the protein kinases are related to diseases including cancer. Nowadays, the purification and identification of kinase and phosphatase are still difficult because commercial vectors are unavailable for mass production and recombinant protein kinases purification, and commercial recombinant protein kinases still have low purity and other shortcomings.
The secondary structure of alpha-kinase 1 (ALPK1) is: α-helices overlap in N-terminus, and threonine/serine kinases domain in the C-terminus. There is no sequence homology to conventional protein kinases, and they will mainly phosphorylate at α-helices on substrate of the amino acid. However, the functions of ALPK1 gene is rarely known, and commercially available ALPK1 recombinant protein has disadvantages such as poor expression, only 80% purity, less protein concentration for crystallization, incapability of expression in prokaryotic cells, and mini transfection for eukaryotic cells.